This invention relates generally to fluid pumps which separate gases mixed with the fluids.
More specifically, the instant invention relates to a dry sump oil pump system for automobiles which separates air suspended in the oil which results from a frothing that takes place under the strain of high performance. Furthermore, the instant invention relates to a system of pumping and processing engine oil which ensures that all of the oil is circulated through the entire system and none lingers in different components of the motor, so that the oil can be beneficially recirculated.
Dry sump oil pump systems for automobiles are well known in the prior art. Those who seek improved performance from an automobile such as racers are aware of the advantages that a dry sump system offers over a conventional oil system. In terms of horsepower, reliability and space, even the simpliest dry sump systems offer improvements over the best wet sump. A dry sump system ensures the complete circulation of all the oil in the system thereby accessing the oil to various filters. Furthermore, the oil has a tendency to migrate in the pan in a wet sump system thus the scavange tube may suck air and not oil which leads to engine failure. Therefore, a dry sump system is an integral part of a high performance vehicle such as a race car.
This is well understood in the prior art. However, a further problem exists. High performance vehicles cause a severe foaming and frothing of the circulated oil. Oil with a high percentage of air aerated therein, is less viscous and more likely to suffer breakdown under grueling conditions. Oil breakdown and loss of viscosity results in the failure of engine components which ultimately leads to complete engine failure, and in the case of a racer a disqualification.
Prior art dry sump systems rely upon the misconception that oil drawn from the very bottom of a separate reservoir will have had time to allow the air to separate from the oil. However, studies have shown that aerated oil remains frothy for quite a long period of time, and recirculating oil in this state can result in engine failure when subjected to the demands of high performance. Therefore, a strong felt yet unfulfilled need exists for an apparatus according to the instant invention which separates the air from the oil by means of an impeller and its associated shaft eliminating the air while returning the oil to a reservoir from which the oil pump draws.
The following patents reflect the state of the art of which applicant is aware insofar as they appear to be germane to the patent process:
______________________________________ 3,686,831 Libby 4,088,459 Tazon 3,932,063 Butler 4,093,397 Lovelady 3,758,085 Metschel ______________________________________
Of the references cited, the patent to Libby appears to be the closest to the instant invention, since he teaches the use of a centrifuge type separator wherein a gas and a liquid are introduced along an inlet port 54 and thereafter are caused to translate axially relative to a shaft 50. Thereafter, vanes or impellers 58 cause the liquid to extend outwardly to chamber 60 while the gas continues along parallel to the axis of the shaft and is emitted at passageway 88.
Similarly, the patent to Butler teaches the use of a liquid pump in which a liquid and a gas are introduced in portal 18 and the gas is allowed to escape along passageway 20, while the liquid is thrown outwardly, traveling out of conduit 26.
The remaining references show the state of the art further.
The instant invention is distinguished in that none of the references teach the use of an oil foam separator wherein the need for a gas outlet port has been eliminated by providing apertures on the center of the shaft forming the centrifuge so that gas escapes along the length of the shaft. Furthermore, none of the references teach or render obvious the sandwich construction in which scavanging stages are provided on opposed sides of the centrifuge. Also, the unique configuration of the propeller disc wherein vanes may be completely excluded is not taught in any of the references.